Malicious PDF — malware analysis report

Static analysis result for SHA-256 41b9fd1b199dddf8…

MALICIOUS

PDF

85.0 KB Created: 2021-06-27 18:00:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 5c012c2b4e714c18f26b7c2d47151665 SHA-1: f8c8562dd78e324b087fa661b6d95fb1371f568f SHA-256: 41b9fd1b199dddf89ff05db68d5415e1552eed79d21a065a819d43af3d4fa5fe
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics reveal it functions as a link farm, with many URLs pointing to compromised WordPress sites and other disposable hosting, suggesting a phishing or malware distribution scheme. The presence of numerous external URIs and the PDF_SEO_DISPOSABLE_LINK_FARM heuristic strongly support this attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9964

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://5m-tti.com/uploads/image/files/22900928387.pdf
    • https://majorsagilekvaros.hu/uploads/file/69708413558.pdf
    • http://bascobrunswick.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160a3e0609e7b2---387944250.pdf
    • https://smoothnomad.com/wp-content/plugins/super-forms/uploads/php/files/4ibeoq04tjp19spahfbljcvv1o/82945184775.pdf
    • https://sg-design.top/wp-content/plugins/super-forms/uploads/php/files/72c50c3b09b2c17d114d0c1e0499b64e/gigamejelofenale.pdf
    • https://www.gasserbush.com/wp-content/plugins/super-forms/uploads/php/files/831ea335e6547cfef5fd524f849fbffe/51215469404.pdf
    • https://used-machinetools.ro/app/webroot/files/userfiles/files/52924793142.pdf
    • https://greenturtleproductions.com.au/wp-content/plugins/super-forms/uploads/php/files/a076ceabb90afa22a29d216fb2b04e08/pujixofilinudugil.pdf
    • http://adamlegal.com/userfiles/file/362394020.pdf
    • http://shinies.ru/img/lib/file/55727741421.pdf
    • http://altaprecision.com/userfiles/file/98927539027.pdf
    • http://alhouti.com/userfiles/file/71359924710.pdf
    • http://www.mywil.ch/wp-content/plugins/formcraft/file-upload/server/content/files/160927ce5dc235---nupopubinasone.pdf
    • https://www.clubmanizales.com.co/wp-content/plugins/formcraft/file-upload/server/content/files/160946ebaad811---97998716774.pdf
    • http://ned.ru/uploads/files/deborozagomesafuzasig.pdf
    • http://rilta.net/userfiles/files/45947355693.pdf
    • http://uyaviation.com/wp-content/plugins/formcraft/file-upload/server/content/files/160707e0d94519---11901451250.pdf
    • http://digimaap.com/wp-content/plugins/super-forms/uploads/php/files/jndtgd630gntiot7aumpn989si/setuko.pdf
    • http://sirmamedia.com/ckfinder/userfiles/files/92472559964.pdf
    • http://basaritarim.net/admin/editor_resim/file/nenavenekexuve.pdf
    • https://nnt52.ru/userfiles/file/91329120663.pdf
    • http://www.recetasyconsejos.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c8be02649dc---kazujapiwu.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/3vuEKuznOb8/uplcv?utm_term=simile+for+kids
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000eafa.bin
ec04e033e8ef37174083f225d66a7eb2e11067d02d47be2e763a20e8effca230
pdf-font-stream PDF embedded font (sfnt) at offset 0xEAFA 17412 bytes
font_01_sfnt_off000117f2.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x117F2 16792 bytes
font_02_sfnt_off00013009.bin
276001b3d56ed9d4f5c25ce09bc2ef98863591dc7a220fc80b7c98ce4c36671f
pdf-font-stream PDF embedded font (sfnt) at offset 0x13009 10316 bytes